Outcomes of acute myeloid leukemia patients undergoing allogeneic hematopoietic stem cell transplantation: validation, comparison and improvement of 2022 ELN genetic risk system

The 2022 European LeukemiaNet (ELN) updated the previous risk classification published in 2017 but the prognostic significance for allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains unclear. We enrolled 600 acute myeloid leukemia (AML) patients who underwent allo-HSCT to validate ELN-2022 genetic risk system and compared it with ELN-2017. There were 214 (35.67%), 162 (27.0%), and 224 (37.33%) patients in ELN-2022 favorable-, intermediate-, and adverse-risk group respectively and 86 patients (14.33%) experienced a shift in risk stratification compared to ELN-2017. Median and maximum follow-up time were 2.89 (95% CI 2.67 to 3.03) years and 8.78 years. The median overall survival (OS) was 73.8% (95% CI 67.5% to 80.3%), 63.9% (95% CI 56.7% to 72.0%) and 57.6% (95% CI 50.4% to 65.9%) in ELN-2022 favorable-, intermediate-, and adverse-risk group (P < 0.001). OS shortened significantly as the ELN-2022 risk stratification increased but didn't significantly in ELN-2017 intermediate-risk compared to favorable-risk. Both ELN-2022 and ELN-2017 adverse-risk were associated with increased cumulative incidence of relapse (CIR). Time-dependent receiver operating characteristic (ROC) analysis showed that both ELN-2017 and ELN-2022 risk systems had limited prognostic ability for OS. We modified ELN-2022 risk system with pre-transplant minimal residual disease (MRD) and the modified risk system performed a significantly superior efficacy to ELN-2022 system.